— Frederick II of PrussiaAttributed by Thomas Babington Macaulay, Life of Frederick the Great (1882), pg 48.
Repeated by Thomas Babington Macaulay in a review of "Frederick the Great and his Times. Edited, with an Introduction, by Thomas Campbell, Esq". Edinburgh Review, ISSN 1751-8482, 04/1842, Volume 75, Issue 151, p. 241-242, though it does not appear in the original work.
Knowles, Oxford Dictionary Of Quotations (5th Edition) (Oxford University Press, 1999)